Important Collectors’ Wristwatches, P...

Geneva, Mandarin Oriental Hotel Du Rhône, May 13, 2007

LOT 59

?Mercury Contacts? Léon Hatot, (ATO). Made circa 1937. Interesting ATO ?master? clock without dial, half-second electromagnetic pendulum and using an experimental mercury circuit switch.

CHF 600 - 1,200

EUR 350 - 750 / USD 500 - 1,000

Sold: CHF 3,540

C. Rectangular, black patinated metal, two wall leveling screws, chromed bezel, battery housing at the base, slave connections at the top. M. Brushed steel backplate, two electrical impulse contact arms, mercury contact switch with glass tube, halfsecond electromagnetic pendulum with cylindrical regulator, curved iron bar magnet, two coils, pendulum locking screw below. Dim. 41 x 22 x 8.5 cm. Property of a French Gentleman


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Grading System
Grade: A

Good
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense

Notes

Mercury switches consist of one or more sets of electrical contacts in a sealed glass tube which contains a bead of mercury. The envelope may also contain air, an inert gas or a vacuum. Gravity is constantly pulling the drop of mercury to the lowest point in the tube. When the switch is tilted in the appropriate direction, the mercury touches a set of contacts, thus completing the electrical circuit through those contacts. Tilting the switch the opposite direction causes the mercury to move away from that set of contacts, thus breaking that circuit.